[ofa-general] iSER header

[Erez Zilber]

Ethan Burns wrote:

> Hello,
> 	I have been looking over the latest Linus git repo and I
> stumbled upon, what appears to be, an inconsistency between the iSER
> header used in the kernel and the latest iSER draft
> (draft-ietf-ips-iser-06.txt):
>
> struct iser_hdr {
>         u8      flags;
>         u8      rsvd[3];
>         __be32  write_stag; /* write rkey */
>         __be64  write_va;		<------------------------------
>         __be32  read_stag;  /* read rkey */
>         __be64  read_va;		<------------------------------
> } __attribute__((packed));
>
>
> The two fields `write_va' and `read_va' seem to be extra fields that are
> not defined by the draft.  Won't these fields present interoperability
> issues with conformant iSER implementations?
>
> Any information would be greatly appreciated.
>
> Ethan Burns
> _______________________________________________
> general mailing list
> general at lists.openfabrics.org
> http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general
>
> To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
>   
The iSER header issue was discussed in the open-iscsi list:

http://groups.google.com/group/open-iscsi/browse_thread/thread/23ee18054e8412e6/fd4182f0b141c2da?lnk=gst&q=iSER%2FiWARP+Support+in+version+2.6.20&rnum=1#fd4182f0b141c2da

For some reason, another answer given by Mike Ko does not appear in this
thread. Here it is:

For Infiniband, if both the initiator and the target support Zero-Based
Virtual Address, then the iSER header as defined in the IETF draft will
be used. (Zero-based Virtual Address is used in iWARP but optional to
implement in Infiniband.) However, if either the initiator or the target
in an Infiniband environment does not support Zero-Based Virtual
Address, then the expanded iSER header as defined in the Infiniband
annex is used. This expanded iSER header is only used in Infiniband.
There is no intention to provide a link in the IETF draft since this is
purely an Infiniband issue.

I hope this helps. BTW - do you plan to use the current iSER initiator
code for iWARP?

-- 

____________________________________________________________

Erez Zilber | 972-9-971-7689

Software Engineer, Storage Team

Voltaire – _The Grid Backbone_

__

www.voltaire.com <http://www.voltaire.com/>